Bathroom Mirror with fluorescent tubes turning off at random times

[jazzlover]

Hi, I have a bathroom mirror fitted in 2013 with 2 fluorescent tubes and a pir sensor to operate. Its been working without any issues until a couple of days ago. Now when I turn the light on by passing a hand under the sensor the light will then go off after anything from a minute to 10 minutes. When I then pass my hand under the sensor again I can hear a click as the switch presumably tries to turn the (already off ) tubes off. If I then pass my hand under the switch again the tubes turn back on.

I assume that the fault is the whole switch assembly associated with the PIR (not sure if that's what these sensors are) . Can anyone suggest any tests I can do to check out where the fault lies?

Neither of the tubes flicker or show any indication that they are faulty.

Thanks

 

[loz2754]

It's probably the tubes. There will be an electronic ballast which prevents the tubes from attempting to restart. So no flickering.

 

[jazzlover]

It's probably the tubes. There will be an electronic ballast which prevents the tubes from attempting to restart. So no flickering.

Thanks for that. So would one tube failing cause both to turn off at the same time?

 

[loz2754]

If they're series wired yes.

 

[jazzlover]

If they're series wired yes.

Hi - thanks for that, I removed one tube and other didn't light, so they are obviously wired in series. Have ordered a replacement set of tubes and will let you know if this cures the problem.

 

[jazzlover]

Update. I have changed both tubes and the problem persists so I assume it is definitely the sensor. The mirror was made by Dansani so I contacted them about a replacement and as they have converted all their illuminated bathroom mirrors to LED they have no spares left. Does anyone have any other suggestions?

I havent yet taken the cover off the sensor assembly (pictured below).